Boiler flue protector



Oct. 13, 1942. c. c. CLARK BOILER FLUE PROTECTOR Filed Aug. 2,

INVENTOR CHARLES C. CLARK HYV Patented Oct. 132, 1942 UNITED STATES 2,298,857'.

BoILER FLUE- PROTECTORLA Charles C. Clark, Columbus, `Ohi'o v Application August 2, 1944),"Seri`alV Nl 349:,67155 1 Claim.

This invention pertains to a tubular boiler of the vertical or upright tube or iiue type, and relates particularly to insulating and protecting means tting into the ends of the hues or tubes on the steam end or the ends are above the water level.

Upright orvertical tube boilers are quite generally used, one common use for them being in tailor or clothes pressing shops where they are used for heating the pressers. There are several tubes or ues in a. boiler, the number depending on the size of the tubes. In the boilers commonly used with clothes pressing machines, there `are about twenty-one one inch tubes (outside measurement). With larger tubes of about one and one-half inch diameter, there are about seven of them in a boiler.

The average life of the tubes or nues in boilers used in pressing shops is about twelve to fourteen months, and it has been found that they break down or burn out at the top or steam end only being held in place, or'somepositive means, such as cement or an annular collar may be employed for securing them.

For a better understandingof the inventioiri.v reference may be made to the accompanying` drawing in which:v v i n Fig; 1 is a vertical diametral section of an upright or vertical boiler embodyingmy inventiny Fig. 2 is a fragmentary plan view, on an enlarged scale, of one of the nues or tubes,on line 2-2` of Fig. 1;

Fig. 3 is a vertical diametiai'section of a rule4 and protector online 3 3 of Fig. 2;

and not at the bottom or water end. The break" down is on the outside or water exposed side oi the tubes opposite to the inner wall or fire exposed side. The ends of the tubes on the steam exposed sides will be almost completely corroded and eaten away with the respective opposite bottom ends on the water exposed sides showing little if any deterioration. Apparently the reason for this is that oxidation of the inner side of the tube walls takes place above the water level in the steam area and not below it, but whatever the reason, the deterioration appears to be confined to the upper ends of the tubes on the steam exposed sides and their average life is consequently no longer than that of the upper ends. When the tubes or flues break down or become badly worn, replacement is necessary. For this tube replacement, the entire boiler is taken to the repair shop, and this, of course, requires time and involves much work and expense, besides having the boiler out of use while replacement of tubes is being made.

The aim of this invention is to provide insulating protectors for the steam end of the tubes, which protectors may be xed to the ends of the tubes or readily inserted and detached. A suitable protector is typified by a preformed tube of some refractory material, such as asbestos paper, inserted in the end of the tube. These protectors should be of sufficient thickness to insulate the tubes against extreme heat but not to materially obstruct the heat passage. They also should be constructed to give adequate protection to the upper ends of the tubes without affecting the 55 Fig. 4 is a vertical diametral section of a portion of the protector;

Fig. 5 is a horizontalcross-section on line 5 5 of Fig. 3 v

Fig. 6 is a horizontal cross-section on line 6--6 of Fig'. 3; and

Fig". 7 is a perspective View of one of the protectors.

Referring specifically to the drawing in which like numerals are used to designate like parts, numeral I is a conventional vertical tubular boiler comprising a cylindrical casing 2 with closure ends 3 and 4 riveted or otherwise secured in place The casing is mounted on legs 5 to more conveniently permit a heating unit 6, preferably gas, being disposed beneath the bottom end. The opposite ends of flues or tubes 'I are mounted in the end closures 3 and 4 in any desired manner, such as being integrally formed therewith, welded or otherwise attached. A jacket 8 surrounds the casing wall and projects a substantial distance above the end 3. The projecting end is closed by a cover 9 having a fume outlet I0 provided therein for the ue chamber II formed between closure 3 and cover 9 and connecting with the ues or tube l. The boiler is equipped with any conventional water level gauge I2, a steam pressure indicator I3 in the steam outlet conduit I4, and a safety valve I5.

Inserted in the upper ends of each of the tubes I are protectors I6 which may be made of any refractory material, such as asbestos paper or the like. These protectors have a body I'I of indefinite length, and are of a diameter to lit snugly within the bore of the tube and engage the inner wall thereof. If the protectors are formed of paper rolled with one or more convolutions rto conform to the contour of the bores of the tubes, they tend to unroll and thereby provide a resilient or expansible character which cause them to snugly engage the walls of the tubes at all times.

Other means may be employed for securing the protectors. One or both ends may be provided with adhesive material to adhesively engage the tube walls. This, of course, permanently secures the protectors in place and while permitting ready insertion does not permit ready removal if the protectors are desired to be replaced.

An enlarged end or collar I8, such as a flange may be formed to provide a stop for limiting insertion of the protector in the tube and hold it in position. The protectors, if desired, may, of course, be provided with the enlarged head and also be adhered in position.

Increased insulation may be obtained by having the protector smaller than the bore of the tubes and provided with collars I9 and 2U which snugly fit the bore of the tube, and provide with the tube and the body of the protector .an insulating space or chamber 2|, functioning in addition to the refractory protectors for insulating the tubes in the steam area.

The boiler tubes may be equipped with these protectors at the time of their manufacture or they may be readily inserted therein by the user when the boiler is installed or any time thereafter. They are made in diierent sizes to accommodate tubes of different diameters. No f1tting is necessary, all that is required being merely inserting them in place. If permanent attachnient of the protectors to the tubes is desired, this may be effected by an insulating cement applied between the outside wall of the protector and the inside wall of the tubes. The cement would also function to hold the protectors in place, and when cemented the collars may be omitted, particularly the enlarged end portion I8.

The protector I6, as stated above, may be made of any refractory material molded or otherwise formed to suitable siZe for fitting in the ends of the tube. One preferred manner of fabricating these is to make the body member by helically winding a strip of asbestos paper upon a mandrel in the same manner that tubular paper cores are formed. The strip is Wound in two or more layers, adhered together, and with the seam or joint of one helical wind staggered with the seam or joint of the adjacent helical wind. Thus the seam or joint in one wound layer of the body will be covered and lapped by the strip in the adjacent wound layer.

The adhesive employed for cementing the layers of the body member together is any which is resistant to high temperature so that it will not break down and disintegrate. Sodium silicate has been found satisfactory.

The enlarged portions I8, IS and 20 may be conveniently provided by snugly fitting a ring or collar of the same material as the body member, but of larger diameter, upon the ends of the body member and cementing or otherwise securing them thereto.

A force draft device may be employed to improve the draft. A suitable device comprises a conduit 22 leading from a branch of the steam chamber to the fume outlet. The discharge end in the fume outlet has a small opening and a valve 23 is provided in the conduit for regulation of the draft.

While one embodiment has been described as to details of construction and manner of use for illustrating the invention, it will be understood that there may be various changes Without departing from the spirit of the invention.

I claim:

An expansible refractory member for use in lining the flues of a tubular water boiler comprising an asbestos paper sheet convoluted into an elongated tubular body conforming to the contour of the bore of the ues, and a collar of asbestos paper convolutions secured about the outer wall adjacent one end of the body member.

CHARLES C. CLARK. 

